Improvement in slide-valves of steam-engines



' UNITED f STATES PATENT Ori-fion."

JAcoB BRADLEY, or sr. MAnYs, omo.

IMPROVEMENT lN SLIDE-VALVES OF STEAM-ENGINES.

Specification forming part of Letters Patent No. 41,361, dated January 26, 1864.

Tov all whom it may concern,.-

Be it known that I, JACOB BRADLEY, of St Mtrys, in the county of Auglaize and State of Ohio, have invented a new and useful Improvement in Steam-Engines; and I do hereby declare that the' following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming part ot' this speciiication, in which- Figure l is a vertical longitudinal section of the cylinders and valve of an engine illustrating my invention. Fig. 2 is a longitudin il vertical section of the valve and seat, showing the valve in diiierent positions.

Similar letters of reference indicate corresponding parts in both iigures.

This invention relates to that class of steamengines in which steam of a high pressure is first used in a cylinder of small diameter, and afterward at a lower pressure in a cylinder of larger diameter.

It consists in an improved slide-valve and system of ports for eii'ectin g the induction and eduction of steam to and from the two cylinders.

To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and operation.

A is the smaller and A the larger cylinder, arranged end to end concentric with each other. B is the smaller and C the larger piston,1`1ttedto their respective cylinders, and both attached to the same piston-rod D, which works in a sturling-boX in the partition a, between the two cylinders and another stuffingbox in the outer head of one of the cylinders. The connections of the piston-rod with the crank are not represented, as they may be of any well-known or suitable kind.

E is the slide-valve of the engine, by which the induction and eduction of thel steam are effected, working upon a seat, b, in a steamchest, F, which is arranged upon the smaller or hi ,gh-pressure cylinder B, and which re ceives steam from the boiler by a pipe, Gr. In the seat b there are iive ports, c c d d e, of which the central one, e, communicates with the exhaust or eduction pipe, which leads to the atmosphere or to a condenser, the 'two outer ones, c c', at equal distances from e communicate with the smaller cylinder A, at opposite ends thereof, and the two, d d', between e and c c', communicate with the smaller cylinder A, at opposite ends thereof, and the two, d d', between e and c c communicate by passages ff with opposite ends of the larger or low-pressure cylinder A. The spaces between the ports are of equal width. The slidevalve has two cavities, g g', in its face, similar to the single cavity of the ordinary slidevalve used for a single cylinder. These cavities are each so constructed and arranged as to be capable of covering two of the ports and their intervening space, and that when the valve is at the middle of its stroke it will close the three ports c o e, and its two cavities, g gf, -will each cover one of the ports d d', and the two spaces between the said ports and the ports e and 'c or c', as shown in Fig.

l of the drawings.

The valve is operated in substantially the same manner as thev slidevalve of a singlecylinder engine, and the length of its stroke is such as to cause the ports d d to n be alternately brought by the cavities g g of the valves first into communication with their respective ports c c, and afterward into communication with the port e, one of the ports o c being always open to the steam-chest when the other is open to its respective port d or d, and one of the ports d d being always open tothe exhaust-port e when the other is open to the port d or d. When the pistons are at either end of the stroke, the valve is nearly in the central position shown in Fig. 1, having only such lead77 as may be desired. W'hen the pistons arrive at the lefthand end of their stroke, as shown in Fig. 1, the valve is moving toward theposition shown in red outline in Fig. 2, and the port c commences opening to the steam-chest, the port o to the port df, and the port d to the port e, and steam is admitted from the steam-chest to the left-hand end ofthe high-pressure cylinder A, and from the right-hand end'of that cylinder through the passage f to the left-hand end ofthelow-pressur'e cylinder, and exhausted from the right-hand end of the latter cylinder through the passage f and ports cl and e, and the piston then moves to the right. As the piston completes its movement to the right, the valve which is now moving toward. the left closes the ports o to the steam-chest and c to the low-pressure cylinder, and commences opening c to the steam and c to the port d, which leads to the right-hand end of the lowpressure cylinder, at the saine time opening the port d', which communicates with the left hand end of the low-pressure cylinder, to the exhausbpipe, as shown in black outline in Fig. 2.

V'Vhat I claim as my invention, and desire to secure by Letters Patent, is-

The slide-Vabre E, having two cavities, g g',

incombination with thesystem of ports c c d d e, communicating with the high and 10W pressure cylinders, steam chest7 and exhaustpipe, substantially as herein specied.

JACOB BRADLEY. Witnesses:

L. G. SAWYER,

IRA MCLAIN. 

